Tubing hanger orientation device

ABSTRACT

A well completion system comprises a tubing head which includes a central bore that extends axially therethrough and at least one fluid port that extends through the tubing head to the central bore, a tubing hanger which is supported in the central bore, an alignment pin which is mounted in the fluid port and which comprises a key portion that protrudes into the central bore, and structure for engaging the key portion to orient the tubing hanger relative to the tubing head. In this arrangement a blind flange may be secured to the tubing head over the fluid port to effectively seal the fluid port from the environment.

BACKGROUND OF THE INVENTION

[0001] The present invention is related to a device for orienting a tubing hanger within a tubing head. More particularly, the invention is related to such a device which includes an alignment pin that is mounted in an existing fluid port in the tubing head. The fluid port in turn is sealed by a blind flange, a valve or the like to thereby maintain the pressure integrity of the tubing head.

[0002] In a typical well completion, a tubing hanger is supported in a tubing head or similar component which is mounted over the well bore. The tubing hanger can be configured to support either a single production tubing string or multiple production tubing strings, depending on the requirements of the well. Often, new information is obtained during the drilling and completion of the well which necessitates a switch from a single string completion to a multiple string completion. Since existing tubing heads are typically designed for either a single string completion or a multiple string completion, but not both, such a switch usually requires that the tubing head be replaced, which is an expensive and time consuming process.

[0003] In addition, in multiple string completions the tubing hanger must be oriented relative to the tubing head so that the position of each tubing string can be known. To achieve this orientation, the tubing head typically includes an alignment pin which is usually installed through a dedicated hole in the body of the tubing head. As the tubing hanger is landed in the tubing head, the alignment pin engages a slot in the tubing hanger to thereby force the tubing hanger into the proper radial orientation relative to the tubing head. However, single string tubing heads do not include this alignment pin. Therefore, if a completion is originally provided with a single string tubing head and it is later determined that multiple tubing strings are needed, the original tubing head must be replaced with a multiple string tubing head.

[0004] A possible alternative to replacing a single string tubing head with a multiple string tubing head is to provide the single string tubing head with a dedicated hole for receiving an alignment pin. For completions that start out requiring only a single tubing string, the threaded hole can be closed with a blanking plug. Then, if the completion later requires multiple tubing strings, the blanking plug can be replaced with an alignment pin.

[0005] However, providing a dedicated hole for an alignment pin presents several disadvantages. For example, machining the dedicated hole adds to the production cost of the tubing head. In addition, the alignment pin must be sealed to the tubing head to provide a sufficient pressure barrier between the well bore and the environment; however, this seal can create a potential leak path which is undesirable from a safety and environmental standpoint.

SUMMARY OF THE INVENTION

[0006] In accordance with the present invention, these and other disadvantages in the prior art are overcome by providing a well completion system that comprises a tubing head which includes a central bore that extends axially therethrough and at least one fluid port that extends through the tubing head to the central bore, a tubing hanger which is supported in the central bore, an alignment pin which is mounted in the fluid port and which comprises a key portion that protrudes into the central bore, and means for engaging the key portion to orient the tubing hanger relative to the tubing head. In one preferred embodiment of the invention, the well completion system also includes a blind flange which is secured to the tubing head over the fluid port. In another preferred embodiment of the invention, the well completion system includes a valve which is secured to the tubing head over the fluid port, and the alignment pin is installed through the valve.

[0007] In accordance with one embodiment of the invention, the engaging means comprises an alignment slot which is formed on the tubing hanger. In another embodiment of the invention, the engaging means comprises an alignment slot which is formed on an extension plate that is connected to the tubing hanger.

[0008] In yet another embodiment of the invention, the engaging means includes a guide sleeve which comprises an outer diameter surface, an inner diameter surface, a first alignment slot that is formed on the outer diameter surface, and an alignment key that is connected to the inner diameter surface. The engaging means also includes a second alignment slot which is formed on the tubing hanger. In operation, the key portion engages the first alignment slot to orient the guide sleeve relative to the tubing head, and the alignment key engages the second alignment slot to orient the tubing hanger relative to the guide sleeve. In this manner, the tubing hanger is properly oriented relative to the tubing head.

[0009] In one embodiment of the invention, the alignment pin comprises a base portion which is removably securable in the fluid port, and the key portion extends axially from the base portion into the central bore of the tubing head. In an alternative embodiment of the invention, the alignment pin comprises a base portion which is removably securable in the fluid port and an axial stem which is connected to the base portion. In this embodiment, the key portion is slidably supported on the stem and the alignment pin further includes means for biasing the key portion away from the base portion and toward the central bore of the tubing head.

[0010] In yet another embodiment of the invention, the alignment pin includes a generally tubular sleeve member which is securable in the fluid port and an elongated pin member which is supported in the sleeve member. In this embodiment, the key portion is formed adjacent one end of the pin member and the pin member is axially movable relative to the sleeve member to bring the key portion into or out of the central bore of the tubing head.

[0011] Thus, the present invention offers many advantages over the prior art. By mounting the alignment pin in an existing fluid port in the tubing head, the need to machine a separate, dedicated bore in the tubing head for the alignment pin is eliminated. In addition, since the fluid port can be sealed off by a blind flange or a valve once the alignment pin is installed, the fluid port will safely and effectively seal the central bore from the environment.

[0012] These and other objects and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings. In the drawings, the same reference numbers may be used to denote similar components in the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a cross sectional view of an exemplary well completion system comprising a first embodiment of the tubing hanger orientation device of the present invention;

[0014]FIG. 2 is an enlarged cross sectional view of a portion of the well completion system shown in FIG. 1;

[0015]FIG. 3 is a partial cross sectional view of the upper packoff member of the orientation device of FIGS. 1 and 2;

[0016]FIG. 4 is a partial cross sectional view of the upper packoff member of FIG. 3 showing a portion of a tubing hanger positioned therein;

[0017]FIG. 5 is a cross sectional view of an exemplary installation tool which may be used to install the upper packoff member of FIG. 3;

[0018]FIG. 6 is a cross sectional view of an exemplary well completion system comprising a second embodiment of the tubing hanger orientation device of the present invention;

[0019]FIG. 7 is a front elevation view of the alignment pin component of the orientation device of FIG. 6;

[0020]FIG. 8 is a cross section view of a tubing hanger to which the extension plate component of the orientation device of FIG. 6 is connected;

[0021]FIG. 9 is a perspective view of the extension plate component shown in FIG. 8;

[0022]FIG. 10 is a top plan view of the extension plate component shown in FIG. 8; and

[0023]FIG. 11 is a longitudinal cross sectional view of an alternative alignment pin which may be used in the tubing hanger orientation devices of FIGS. 1 and 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Referring to FIG. 1, the tubing hanger orientation device of the present invention, which is indicated generally by reference number 10, is shown installed in an exemplary well completion system 12, which for purposes of the present invention can be any assembly of components that is used to complete either a surface or a subsea well. For example, the well completion system 12 may comprise a wellhead housing 14 which is connected to the upper end of an outer casing string 16 that extends into the well bore, a tubing head 18 which is secured to the top of the wellhead housing and which includes a central bore 20 that extends axially therethrough, a tubing hanger 22 which is supported in the central bore, and an optional flowline adapter 24 which is connected to the top of the tubing head. The well completion system 12 is a multiple string completion and accordingly comprises at least two production tubing strings 26, each of which is suspended from the tubing hanger 22 and extends into the well formation through an inner casing string 28. The casing string 28 is suspended within the outer casing string 16 from either a slip-type casing hanger 30 (shown on the left hand side of FIG. 1), or a mandrel-type casing hanger 32 (shown on the right hand side of FIG. 1), that in turn is landed in the wellhead housing 14.

[0025] The tubing head 18 can be any well component within which a tubing hanger is supported, such as a tubing spool, a Christmas tree or a spool tree. In addition, the tubing head 18 typically comprises a number of fluid ports which each extend through tubing head to the central bore 20 to provide selective access to various portions of the well bore. In the exemplary flow completion system 12, for example, the tubing head 18 is shown to comprise first and second annulus ports 34 and 36, respectively, which each communicate with the production tubing annulus between the production tubing strings 26 and the inner casing string 28. The first annulus port 34 is connected to a valve 38 which may be opened to monitor or relieve the pressure in the production tubing annulus. The second annulus port 36 is closed off by a blind flange 40, which is bolted and sealed to the tubing head 18.

[0026] Referring also to FIG. 2, the tubing hanger orientation device 10 comprises an alignment pin 42 which is mounted in the second annulus port 36 and which engages a corresponding alignment slot 44 on a guide sleeve 46 to thereby orient the guide sleeve relative to the tubing head 18. The guide sleeve 46 in turn comprises an alignment key 48 which engages a corresponding alignment slot 50 on the tubing hanger 22 as the tubing hanger is lowered into the tubing head 18 to thereby force the tubing hanger into the proper orientation relative to the guide sleeve. Thus, once the tubing hanger 22 is fully landed, the tubing hanger will be properly oriented relative to the tubing head 18.

[0027] As shown in FIG. 2, the alignment pin 42 comprises a cylindrical base portion 52 which is removably secured in the annulus port 36 such as by threads 54. An axial stem 56 is connected to or formed integrally with the base portion 52, and a cylindrical key portion 58 is slidably supported on the stem. The key portion 58 is ideally biased away from the base portion 52 by a spring 60, which is preferably mounted over the stem between the key portion and the base portion. In this manner, when the guide sleeve 46 is properly oriented relative to the tubing head 18, the spring 60 will force the key portion 58 into the alignment slot 44. The alignment pin 42 may also include suitable means to limit the extension of the key portion 58 prior to installation, such as a washer 62 which is secured to the end of the stem 56 and is adapted to engage a corresponding shoulder that is formed on the inner diameter surface of the key portion.

[0028] In a preferred embodiment of the invention, the alignment pin 42 also includes an annular shoulder 64 between the base portion 52 and the stem 56 which engages a corresponding seat in the annulus port 36 to thereby form a fluid and pressure tight, preferably metal-to-metal seal between the alignment pin and the annulus port. Such a metal-to-metal seal will effectively seal the annulus port from the external environment, thereby obviating the need for the blind flange 40. Accordingly, the alignment pin 42 may be installed in a dedicated hole in the tubing head 18, rather than in a pre-existing fluid port such as the annulus port 36, provided the dedicated hole is provided with a seat against which the shoulder 64 may seal.

[0029] Referring to FIGS. 2 through 4, the guide sleeve 46 may be, for example, an upper packoff member which is part of a packoff assembly that also includes a lower packoff member 66. The lower packoff member 66 comprises a generally cylindrical body 68 on which are mounted a first annular seal 70 for sealing the body against the wellhead housing 14, a second annular seal 72 for sealing the body against the tubing head 18, and preferably third and fourth annular seals 74 and 76, respectively, for sealing the body against either the mandrel casing hanger 32 or the inner casing string 28 (when the slip-type casing hanger 30 is employed instead of the mandrel casing hanger).

[0030] As shown most clearly in FIG. 3, the upper packoff member 46 includes a generally tubular wall portion 78 which comprises an inner diameter surface 80 and an outer diameter surface 82, an annular shoulder 84 which extends radially inwardly from the outer diameter surface proximate a lower end of the wall portion, a circular lip 86 which projects radially inwardly from the inner diameter surface proximate the lower end of the wall portion, and a cylindrical flange 88 which depends downwardly from the shoulder. The alignment slot 44 is formed on the outer diameter surface 82 of the wall portion 78 and preferably comprises a width that is only slightly larger than the corresponding portion of the key portion 58 to prevent the upper packoff member 46 from rotating relative to the tubing head 18 once the alignment key 42 is engaged in the alignment slot. Referring also to FIG. 4, the alignment key 48 is preferably a separate member which is secured such as by welding in a corresponding recess 90 that is formed on the inner diameter surface 80 of the wall portion 78. The alignment key 48 also ideally comprises a sloped upper end 92 to more easily mate with the alignment slot 50 in the tubing hanger 22 as the tubing hanger is landed in the tubing head 18.

[0031] Prior to being installed in the tubing head 18, the upper packoff member 46 is preferably assembled with the lower packoff member 66 in the following manner. First, the flange 88 is inserted into a corresponding recess 94 which is formed adjacent the upper end of the body 68. The upper packoff member 46 is then secured to the lower packoff member 66 with a number of screws 96, each of which extends through a hole in the flange and into an annular groove 98 which is formed in the recess 94. In this manner, the upper packoff member 46 is secured to the lower packoff member 66 but is free to rotate relative thereto.

[0032] The packoff assembly is installed using a suitable tool, such as the running and retrieval tool (“R & R tool”) 100 shown in FIG. 5. The R & R tool 100 includes an upper end 102 that may be connected to a string of drill pipe or the like (not shown), and an outer surface portion 104 which comprises a diameter that is preferably only slightly smaller than the diameter encompassed by the lip 86 of the upper packoff member 46. A number of lugs 106 are secured in corresponding holes formed in the outer surface portion 104. The lugs 106 are adapted to engage corresponding J-slots 108 which extend axially through the lip 86 of the upper packoff member 46 (see FIG. 4). The packoff assembly is secured to the R & R tool 100 by sliding the packoff assembly over the R & R tool until the lugs 106 enter the J-slots 108, and then rotating the packoff assembly until the lugs are trapped under the lip 86.

[0033] During installation of the packoff assembly, the annulus port 36 is preferably sealed with a blanking plug (not shown). The packoff assembly is connected to the R & R tool 100 in the manner described above, and then lowered into the tubing head 18 until the lower packoff member 66 seats against the casing hanger 30, 32. As shown in FIG. 2, the lower packoff member 66 may then be locked to the tubing head 18 with a plurality of lockdown bolts 110. At this point, the blind flange 40 is removed, the blanking plug is replaced with the alignment pin 42, and the blind flange is preferably reinstalled on the tubing head 18 to ensure that the annulus port 36 is suitably sealed from the external environment. Using the R & R tool 100, the upper packoff member 46 is rotated relative to the lower packoff member 66 until the alignment slot 44 is positioned opposite the alignment pin 42, whereupon the key portion 58 will snap into the alignment slot to maintain the upper packoff member properly oriented relative to the tubing head 18.

[0034] Once the upper packoff member 46 is properly oriented in the tubing head 18, the R & R toll 100 can be retrieved and the tubing hanger 22 installed. The tubing hanger 22 is lowered into the tubing head 18 until the bottom of the tubing hanger engages the top surface 92 of the alignment key 48. The tubing hanger 22 is then rotated until the alignment key 48 enters the alignment slot 50. As shown most clearly in FIG. 2, the lower side portions of the alignment slot 50 are dovetailed outwardly as at 112 to facilitate the engagement of the alignment key 48 with the alignment slot. Therefore, once the tubing hanger 22 is fully seated in the tubing head 18, the tubing hanger will be properly oriented relative to the upper packoff member 46 and, thus, the tubing head.

[0035] Referring now to FIG. 6, another embodiment of a tubing hanger orientation device according to the present invention, which is indicated generally by reference number 210, is shown installed in an exemplary well completion system 212. As with the well completion system 12, the well completion system 212 can be any assembly of components which is used to complete either a surface or a subsea well. For purposes of simplicity, the well completion system 212 is only shown to comprise a tubing head 214 which comprises a central bore 216 that extends axially therethrough, a tubing hanger 218 which is supported in the central bore, a flowline adapter 220 which is secured to the top of the tubing head, and a production tubing string 222 which is suspended from the tubing hanger 218. The tubing head 214 is connected to the upper end of a casing string 224 which extends into the well bore, and the production tubing string 222 extends into the well formation through the casing string 224. The flow completion system 212 may also comprise a signal or power line connector 226, which includes a coupling member 228 that is mounted in a corresponding bore 230 in the tubing hanger 218 and is connected through a suitable line 232 to a device which is located in the well bore (not shown).

[0036] The tubing head 214 can be any well component within which a tubing hanger is supported, such as a tubing spool, a Christmas tree or a spool tree. In addition, the tubing head 214 typically comprises a number of fluid ports which each extend through the tubing head to the central bore 216 to provide selective access to various portions of the well bore. For example, the tubing head 214 is shown to comprise first and second annulus ports 234 and 236, respectively, which each communicate with the production tubing annulus between the production tubing string 222 and the casing string 224. The first annulus port 234 may be connected to a valve (not shown), which may be similar to the valve 30 described above. The second annulus port 236 is preferably closed off by a blind flange (not shown), which may be similar to the blind flange 40 discussed above.

[0037] In accordance with this embodiment of the invention, the tubing hanger orientation device 210 comprises an alignment pin 238 which is mounted in the second annulus port 236 and engages a corresponding alignment slot 240 in an extension plate 242 that is connected to the bottom of the tubing hanger 218. In this manner, as the tubing hanger 218 is landed in the tubing head 214, the alignment slot 240 will engage the alignment pin 238 and force the tubing hanger into the proper orientation relative to the tubing head.

[0038] Referring to FIG. 7, the alignment pin 238 comprises a cylindrical base portion 244 which includes a threaded outer diameter surface 246, an annular shoulder 248 which is formed adjacent the base portion, and a preferably cylindrical key portion 250 which extends axially from the shoulder. During assembly of the flow completion system 212, the alignment pin 238 is threaded into the annulus port 236 until the shoulder 248 engages a corresponding shoulder in the annulus port. In this position, the key portion 250 will extend sufficiently into the bore of the tubing head 214 to be engaged by the extension plate 242. In a preferred embodiment of the invention, the shoulder 248 engages a corresponding seat in the annulus port 236 to thereby form a fluid and pressure tight metal-to-metal seal between the alignment pin 238 and the annulus port that will effectively seal the annulus port from the external environment. The blind flange may then be bolted to the tubing head 214 to ensure that the annulus port 236 is sufficiently sealed from the environment.

[0039] Referring to FIGS. 8 through 10, the extension plate 242 ideally comprises a generally semi-cylindrical body 252 which has a curved outer wall 254 and a substantially flat inner face 256. The outer wall 254 comprises an upwardly extending flange 258 which is adapted to be received in a corresponding annular groove 260 that is formed in the bottom of the tubing hanger 218. The alignment slot 240 extends axially through the outer wall 254 and preferably includes outwardly flared lower side portions 262 to facilitate the engagement of the alignment slot with the alignment pin 238. The extension plate 242 also preferably includes an axial through hole 264 which aligns with the bore 230 when the extension plate is attached to the tubing hanger 218 and accordingly permits the line 232 to pass from the coupling member 228 to the production tubing annulus. In addition, the alignment slot 240 is ideally connected to the through bore 264 to permit the extension plate 242 to be attached to the tubing hanger 218 after the coupling member 228 and the line 232 have been installed. The extension plate 242 may be attached to the tubing hanger 218 by any suitable means, such as a number of bolts (not shown) which extend through corresponding holes 266 in the body 252 and into the bottom of the tubing hanger.

[0040] Prior to running the tubing hanger 218 into the tubing head 214, the alignment pin 238 is installed in the annulus port 236, which is then securely closed off by the blind flange. The tubing hanger 218 is then lowered into the tubing head 214 until the extension plate 242 engages the alignment pin 238. At this point, the tubing hanger 218 is rotated until the alignment pin 238 engages one of the flared lower side portions 262 of the alignment slot 240. As the tubing hanger 218 is lowered further, the alignment pin 238 will progress up the alignment slot 240 and force the tubing hanger into the proper orientation relative to the tubing head 218.

[0041]FIG. 11 illustrates an alternative alignment pin which may be used with either of the tubing hanger orientation devices described above. In this embodiment of the invention, the alignment pin, generally 268, is shown to comprise an elongated pin member 270 which is movably supported in a generally tubular sleeve member 272 that is preferably removably secured in the annulus port 36, 236. The pin member 270 includes a key portion 274 which is formed adjacent one end thereof, a tool preparation 276 which is formed at an opposite end thereof, and a threaded outer diameter section 278. The sleeve member 272 includes a threaded outer diameter portion 280, an annular outer shoulder 282, a cylindrical inner sealing surface 284, and a threaded inner diameter section 286 which is adapted to mesh with the threaded outer diameter section 278 of the pin member 270. The alignment pin 268 ideally also includes at least one and preferably two annular seals 288, which in the illustrative embodiment are shown mounted on the pin member 270. These seals 288, which are preferably made of a non-metallic material, provide a fluid and pressure tight seal between the pin member 270 and the sleeve member 272.

[0042] In use, the alignment pin 268 is threaded into the annulus port 36, 236 until the shoulder 282 engages a corresponding shoulder in the annulus port, which engagement preferably forms a fluid and pressure tight metal-to-metal seal between the sleeve member 272 and the annulus port. The sleeve member ideally includes a hex profile 290 to aid in installing the alignment pin 268 in the annulus port 36, 236. Due to the threaded connection between the pin member 270 and the sleeve member 272, rotation of the pin member will cause the pin member to move axially relative to the sleeve member. Accordingly, once the alignment pin 268 is installed in the annulus port 36, 236, the key portion 274 can be selectively extended into or retracted from the central bore of the tubing head as needed to orient the tubing hanger relative to the tubing head. In this regard, the tool preparation 276 can be adapted to accommodate any tool which may be used to rotate the pin member 270 relative to the sleeve member 272.

[0043] Although the foregoing embodiments have been described with the alignment pin installed in a fluid port that is preferably closed off by a blind flange, the present invention contemplates that the alignment pin could be installed in a fluid port that is instead connected to a valve. For example, the alignment pin could be installed in the annulus port 34 shown in FIG. 1. The annulus port 34 is connected to a valve 38, which may be, for example, a conventional gate valve. In such an embodiment, the alignment pin could be installed by first removing the valve 38 from the tubing head 18. However, the alignment pin is preferably installed, adjusted and, if necessary, removed through the valve 38. This may be accomplished with the aid of a lubricator that is mounted to the valve 38 in order to maintain a pressure barrier between the annulus port 34 and the environment when the valve is in the open position. The use of a lubricator in this manner is well known in the art and need not be further described herein.

[0044] It should be recognized that, while the present invention has been described in relation to the preferred embodiments thereof, those skilled in the art may develop a wide variation of structural and operational details without departing from the principles of the invention. For example, the various elements shown in the different embodiments may be combined in a manner not illustrated above. Therefore, the appended claims are to be construed to cover all equivalents falling within the true scope and spirit of the invention. 

What is claimed is:
 1. A well completion system which comprises: a tubing head which includes a central bore that extends axially therethrough and at least one fluid port that extends through the tubing head to the central bore; a tubing hanger which is supported in the central bore; an alignment pin which is mounted in the fluid port and which comprises a key portion that protrudes into the central bore; and means for engaging the key portion to orient the tubing hanger relative to the tubing head.
 2. The well completion system of claim 1, further comprising a blind flange which is secured to the tubing head over the fluid port.
 3. The well completion system of claim 1, further comprising a valve which is secured to the tubing head over the fluid port.
 4. The well completion system of claim 3, wherein the alignment pin is installed in the fluid port through the valve.
 5. The well completion system of claim 1, wherein the engaging means comprises an alignment slot which is formed on the tubing hanger.
 6. The well completion system of claim 1, wherein the engaging means comprises an alignment slot which is formed on an extension plate that is connected to the tubing hanger.
 7. The well completion system of claim 6, wherein the tubing hanger comprises at least one bore which extends longitudinally therethrough and the extension plate comprises a through hole which aligns with the bore when the extension plate is connected to the tubing hanger.
 8. The well completion system of claim 7, wherein the alignment slot is connected to the through hole.
 9. The well completion system of claim 8, wherein the extension plate is secured to the bottom of the tubing hanger.
 10. The well completion system of claim 1, wherein the engaging means comprises: a guide sleeve which comprises an outer diameter surface, an inner diameter surface, a first alignment slot that is formed on the outer diameter surface, and an alignment key that is connected to the inner diameter surface; and a second alignment slot which is formed on the tubing hanger; wherein the key portion engages the first alignment slot to orient the guide sleeve relative to the tubing head and the alignment key engages the second alignment slot to orient the tubing hanger relative to the guide sleeve.
 11. The well completion system of claim 10, wherein the guide sleeve comprises a lip which extends radially inwardly from the inner diameter surface and a number of J-slots which extend axially through the lip.
 12. The well completion system of claim 11, further comprising: a running and retrieval tool which comprises a number of lugs that are adapted to engage the J-slots; wherein the running and retrieval tool may be used to install the guide sleeve in the tubing head and to orient the guide sleeve relative to the tubing head.
 13. The well completion system of claim 10, further comprising: a wellhead housing which is positioned below the tubing head and which supports a casing hanger from which a casing string is suspended; wherein the guide sleeve comprises an upper packoff member; and wherein the upper packoff member is rotatably secured to a lower packoff member that seals between the wellhead housing and at least one of the casing hanger and the casing string.
 14. The well completion system of claim 13, wherein the upper packoff member is rotatable relative to the lower packoff member to bring the first alignment slot into engagement with the key portion.
 15. The well completion system of claim 14, wherein the upper packoff member comprises a lip which extends radially inwardly from the inner diameter surface and a number of J-slots which extend axially through the lip.
 16. The well completion system of claim 15, further comprising: a running and retrieval tool which comprises a number of lugs that are adapted to engage the J-slots; wherein the running and retrieval tool may be used to install the upper and lower packoff members and to orient the upper packoff member relative to the tubing head.
 17. The well completion system of claim 1, wherein the alignment pin further comprises a base portion which is removably securable in the fluid port, and the key portion extends axially from the base portion.
 18. The well completion system of claim 17, wherein the alignment pin further comprises an annular shoulder which is adapted to engage a corresponding shoulder in the fluid port to form a seal between the alignment pin and the fluid port.
 19. The well completion system of claim 1, wherein the alignment pin further comprises: a base portion which is removably securable in the fluid port; an axial stem which is connected to the base portion; wherein the key portion is slidably supported on the stem; and means for biasing the key portion away from the base portion and toward the central bore of the tubing head.
 20. The well completion system of claim 19, wherein the biasing means comprises a spring which is mounted over the stem between the base portion and the key portion.
 21. The well completion system of claim 19, wherein the alignment pin further comprises means for limiting the movement of the key portion into the central bore of the tubing head.
 22. The well completion system of claim 21, wherein the limiting means comprises a washer which is secured to an end of the stem opposite the base portion and which engages a corresponding shoulder formed on an inner diameter surface of the key portion.
 23. The well completion system of claim 19, wherein the alignment pin further comprises an annular shoulder which is formed adjacent the base portion and which is adapted to engage a corresponding shoulder in the fluid port to form a seal between the base portion and the fluid port.
 24. The well completion system of claim 1, wherein the alignment pin further comprises: a generally tubular sleeve member which is securable in the fluid port; and an elongated pin member which is supported in the sleeve member and which comprises the key portion adjacent one end thereof; wherein the pin member is axially movable relative to the sleeve member to bring the key portion into or out of the central bore of the tubing head.
 25. The well completion system of claim 24, wherein the pin member comprises a threaded outer diameter section and the sleeve member comprises a threaded inner diameter section which is adapted to engage the threaded outer diameter section, wherein rotation of the pin member relative to the sleeve member will move the pin member axially relative to the sleeve member.
 26. The well completion system of claim 25, wherein the pin member further comprises a tool preparation which is formed adjacent an end opposite the key portion.
 27. The well completion system of claim 24, wherein the sleeve member further comprises an annular shoulder which is adapted to engage a corresponding shoulder in the fluid port to form a seal between the sleeve member and the fluid port.
 28. The well completion system of claim 27, further comprising means for sealing between the pin member and the sleeve member.
 29. The well completion system of claim 1, further comprising: a wellhead housing which is positioned below the tubing head and which supports a casing hanger from which a casing string is suspended; and a packoff assembly which comprises a lower packoff member that seals between the wellhead housing and at least one of the casing hanger and the casing string and an upper packoff member that is rotatably secured to the lower packoff member; wherein the engaging means comprises the upper packoff member and a first alignment slot which is formed on the tubing hanger; wherein the upper packoff member comprises an outer diameter surface, an inner diameter surface, a second alignment slot that is formed on the outer diameter surface, and an alignment key that is connected to the inner diameter surface; wherein the key portion engages the second alignment slot to orient the upper packoff member relative to the tubing head and the alignment key engages the first alignment slot to orient the tubing hanger relative to the upper packoff member.
 30. The well completion system of claim 29, wherein the alignment pin further comprises: a base portion which is removably securable in the fluid port; an axial stem which is connected to the base portion; wherein the key portion is slidably supported on the stem; and means for biasing the key portion away from the base portion and toward the central bore of the tubing head.
 31. The well completion system of claim 30, wherein the upper packoff member is rotatable relative to the lower packoff member to bring the second alignment slot into alignment with the key portion, whereupon the key portion will extend into the second alignment slot to thereby maintain the upper packoff member properly oriented relative to the tubing head.
 32. The well completion system of claim 31, wherein the biasing means comprises a spring which is mounted over the stem between the base portion and the key portion.
 33. The well completion system of claim 31, wherein the alignment pin further comprises an annular shoulder which is formed adjacent the base portion and which is adapted to engage a corresponding shoulder in the fluid port to form a seal between the base portion and the fluid port.
 34. A well completion system which comprises: a tubing head which includes a central bore that extends axially therethrough and a hole that extends through the tubing head to the central bore; a tubing hanger which is supported in the central bore; an alignment pin which comprises a base portion that is removably securable in hole, an axial stem that is connected to the base portion, a key portion that is slidably supported on the stem, and means for biasing the key portion away from the base portion and toward the central bore; and means for engaging the key portion to orient the tubing hanger relative to the tubing head.
 35. The well completion system of claim 34, wherein the biasing means comprises a spring which is mounted over the stem between the base portion and the key portion.
 36. The well completion system of claim 34, wherein the alignment pin further comprises means for limiting the movement of the key portion into the central bore.
 37. The well completion system of claim 36, wherein the limiting means comprises a washer which is secured to an end of the stem opposite the base portion and which engages a corresponding shoulder formed on an inner diameter surface of the key portion.
 38. The well completion system of claim 34, wherein the alignment pin further comprises an annular shoulder which is formed adjacent the base portion and which is adapted to engage a corresponding shoulder in the hole to form a seal between the base portion and the hole.
 39. The well completion system of claim 34, wherein the engaging means comprises an alignment slot which is formed on the tubing hanger.
 40. The well completion system of claim 34, wherein the engaging means comprises an alignment slot which is formed on an extension plate that is connected to the tubing hanger.
 41. The well completion system of claim 34, wherein the engaging means comprises: a guide sleeve which comprises an outer diameter surface, an inner diameter surface, a first alignment slot that is formed on the outer diameter surface, and an alignment key that is connected to the inner diameter surface; and a second alignment slot which is formed on the tubing hanger; wherein the key portion engages the first alignment slot to orient the guide sleeve relative to the tubing head and the alignment key engages the second alignment slot to orient the tubing hanger relative to the guide sleeve.
 42. The well completion system of claim 41, further comprising: a wellhead housing which is positioned below the tubing head and which supports a casing hanger from which a casing string is suspended; wherein the guide sleeve comprises an upper packoff member; and wherein the upper packoff member is rotatably secured to a lower packoff member that seals between the wellhead housing and at least one of the casing hanger and the casing string. 